Composite conveyor belts have been used in the past where the belt includes a plurality of components such as, for example, a flat belt and a toothed timing component running the length of the belt and preferably centrally located, and other components. The flat belt portion is constructed to convey objects while the timing component typically comprises a plurality of laterally extending teeth for operative cooperation with a complimentary configured drive pulley or timing drive wheel. Rotation of the wheel drives the composite belt along operative and return runs and around and along the drive wheel and any idler or support rollers, tails stocks or the like. Many such belts include additional components such as layers of wear resisting material on the timing component side of the belt.
Such prior belts typically and inherently present at least two pitch lines defined by the belt components. For example, the flat belt component may present a first one pitch line while the toothed timing component presents yet another second pitch line spaced away from the first pitch line. Alternatively, additional wear or other function layers present other pitch lines.
When such a belt is entrained around a drive wheel or tail stock, for example, the presence of two or more pitch lines can urge or bias the respective belt components (with respect to each respective pitch line) in a manner which can cause undue belt wear, observed as delamination, of one component from the other. This undesirable wear and separation increases as the diameter of the drive wheel and or tail stock, for example, decreases. And in some instances, depending on the materials of the belt components, diameter of the drive and support wheels, loads and speeds, such component belts wear to a point of practical uselessness, and must be replaced with costly frequency.
Thus, certain co-formed (or “homogenous”) two-component belts of the prior art, such as a flat belt with timing structure, inherently include a single pitch line simply by virtue of their integral, unitary construction. However, the timing components of these known co-formed belts are lacking because they provide limited tracking abilities, produce increased noise or are prone to accelerated wear in high-speed applications, thus requiring frequent replacement which results in financial burden for the operator.
Attempts have been made to increase the functional longevity of such homogeneous component belts. In such attempts by others, where component belts have been formed by the co-forming of a belt component and a timing component initially with a single pitch line, the addition of necessary further component material laminations result in a composite belt still inherently presenting, undesirably, two separate and spaced pitch lines.
An improved timing component, such as that referred to as the “Eagle” timing belt, has been used in conveyor belts with the advantage of noise reduction. Such a component is described in U.S. Pat. Nos. 5,209,705; 5,421,789; 6,183,582; and 6,672,983, for example, each of which is expressly incorporated herein by reference. Advantages provided by the “Eagle” type timing belt include self-tracking abilities, improved durability in high speed applications, and reduced noise production.
As indicated above, a primary advantage offered by a two component co-formed belt where the timing component is of any variety, is inclusion of a belt component and a timing component while maintaining a single belt pitch line. The single belt pitch line allows for increased flexibility of the belt as compared to multiple-part manufactured belts having multiple pitch lines corresponding to multiple bonded layers. However, there are no now known conveyor belts having an “Eagle”-type timing component co-formed with a flat belt and together with other desired belt components, such as wear resistant components, without the finished belt having two pitch lines as discussed above.
Accordingly, it is desired to provide an improved conveyor belt having at least a belt component, and other timing components but without any undue wear or delamination resulting from two inherent pitch lines.
A further objective has been to provide a timed conveyor belt useful in a wide range of applications independent of the diameter of timed driving or support wheels.
A further objective of the invention has been to provide a composite conveyor belt having a single pitch line and with an “Eagle” style timing component and with antiwear layers but without the tendency to wear or delaminate due to having two spaced pitch lines.
A yet further objective of the invention has been to provide an improved composite belt having a flat belt component, a timing belt component, and at least one further layer or component but where the composite belt presents only one pitch line.
A further objective of the invention has been to provide a method of forming an improved composite conveyor belt having a belt component, a timing component and additional component layers, all with a single functional pitch line.